Apparatus and method for determining the viability of eggs

ABSTRACT

An apparatus ( 10 ) for determining the viability of an egg, which apparatus ( 10 ) comprises shielding means ( 12, 14 ), emitting means ( 30 ) and detecting means ( 32 ), the arrangement being such that, in use, the shielding means ( 12, 14 ) inhibits exposure of an egg to background infra-red radiation, said emitting means ( 30 ) can emit electromagnetic radiation at infra-red wavelength(s) to impinge on the egg, and the detecting means ( 32 ) are positioned to detect at least a part of said electromagnetic radiation that has passed through the egg, the apparatus further comprising means for processing an output signal of the detecting means to determine whether there is a cyclical variation in the intensity of the infra-red radiation leaving the egg corresponding to action of a heart, the existence of said cyclical variation indicating that the egg is viable.

FIELD OF INVENTION

The present invention relates to an apparatus and method for determiningthe viability of eggs laid by egg-laying animals, and in particular butnot exclusively, to eggs laid by reptiles and birds, for exampleparrots.

BACKGROUND

Once an egg has been laid by an animal, it must undergo a period ofincubation, either naturally or artificially, during which timedevelopment of the young animal takes place. Many birds for example, siton an egg or clutch of eggs in order to regulate temperature andhumidity around the egg(s), such regulation being crucial for thesurvival and proper development of the embryo inside each egg. Otheranimals utilise different sources, for example solar or geothermalenergy, for this purpose. Alternatively, incubation may be carried outand/or assisted by man. Man-made incubators are well known that can holda number of eggs and which provide artificial temperature and humidityregulation of the air around the eggs.

Many breeders and conservationists of egg-laying animals need to knowwhether or not the embryo is alive and developing at the proper rateinside the egg. Such knowledge is required throughout the incubationperiod, and is important both in natural and artificial incubationscenarios in order to maximise the chances of survival of the young. Innatural incubation, for example a clutch of eggs brooded by a bird, ifone or more embryos does not survive, those eggs can become infected bybacteria and endanger the remaining eggs. Furthermore, some species ofparrot for example the Palm Cockatoo, Black Cockatoo and HyacinthineMacaw, can only lay fertile eggs during a short period of time each yearand even then only incubate one egg at a time. If that egg does notsurvive, the opportunity for successful breeding has been missed forthat year. Such scenarios can have serious implications for endangeredspecies, and for breeders and keepers of such birds who exchange themfor considerable sums of money. The situation is analogous for manyspecies of egg-laying animal.

At present there are two well known methods for checking the fertilityand development of eggs. The first method, known as “candling”, involvesplacing an egg in front of an intense light source, for example tungstenhalogen, so that the inside of the egg is visible to the naked eye, andlooking for signs of growth e.g. vein development that is first visibleafter approximately four days in parrot eggs. Over the next few days itis possible to check for further growth by looking for increasingnumbers and density of veins and a growing “dark spot” in the centre ofthe egg. However, there are three disadvantages with “candling”, thefirst being that a high intensity of light is required to see into theegg meaning that it is exposed to high temperature levels that candamage or kill the embryo in the egg if held over the light for toolong. Secondly, the “dark spot” grows at such a rate that afterapproximately twelve days (in parrot eggs) it occupies so much of thevolume of the egg that the veins are no longer visible and it is notpossible to tell whether or not the young bird is alive. Thirdly, someeggs are not suitable for “candling” such as raptors, falcons, ducks andwild fowl, whose eggs range from dark green to dark brown in colour, andother species whose shells are so dense that the light from the lampcannot pass through them. For such eggs it is not possible to tellwhether or not they are fertile and alive in the first few days.

The second known method addresses the second and third problemsmentioned above. This method involves floating the egg in still warmwater and waiting for the egg to move as a result of movement of theyoung animal inside. There are two disadvantages associated with thismethod, the first being that the method is unreliable and slow since itrelies on a parameter that is inherently random. Secondly, immersing theegg in water exposes it to bacteria that can pass through the shell,particularly as the egg is withdrawn from the water, when water on thesurface of the egg tends to be “sucked” in through the pores of theshell severely reducing the egg's ability to self-regulate humidity.Once inside the shell the bacteria and water are in an ideal environmentat 37° C. to multiply, potentially endangering the life of the younganimal.

U.S. Pat. No. 5,745,228 discloses an apparatus for distinguishing livefrom infertile poultry eggs at high speed in the presence of ambient (orbackground) light. The apparatus comprises a photoemitter for emittinginfra-red radiation located directly opposite a photodetector. In useeggs pass at high speed (10 inches per second is suggested) between thephotoemitter and photodetector on a conveyor. The photodetector isturned on and off 100 times per second in bursts of 250 μs. Thephotodetector takes readings when the photoemitter is actuated and whende-activated; by subtracting these readings the effects of ambient lighton the signal are reduced. The apparatus only has sufficient resolutionto classify eggs into three groups namely, clear or early dead, middead, and live. These results are not significantly better than can beobtained by the aforementioned method of candling.

FR 2 455 282 discloses an improved candling method in which infra redlight is passed through an egg in the presence of background light.Light having passed through the detector is detected and the outputsignal displayed on a visual display screen. The viability of the egg isdetermined by comparison of the relative intensity of the receivedsignal either visually or automatically.

However, the disadvantage with the aforementioned publications is thatonly differences in the received intensity of light from each egg can becompared in order to make an assessment of the viability of an egg.

Thus, it is apparent that there is a need for an apparatus and method oftesting the viability of eggs that is more reliable, that minimises therisks to which prior methods have exposed eggs, and which facilitatesmaximisation of the chances of survival of fertile eggs.

SUMMARY OF THE INVENTION

The present invention is based on an insight into the effect thatstructures in viable eggs have on infra-red light passing therethrough.This effect is present from approximately 5 to 12 days (depending on thespecies of animal) up until the animal hatches from the egg.

According to one aspect of the present invention, there is provided anapparatus for determining the viability of an egg, which apparatuscomprises shielding means, emitting means and detecting means, thearrangement being such that, in use, the shielding means inhibitsexposure of an egg to background infra-red radiation, said emittingmeans can emit electromagnetic radiation at infra-red wavelength(s) thatimpinge on the egg, the apparatus further comprising means forprocessing an output signal of the detecting means to determine whetherthere is a cyclical variation in the intensity of the infra-redradiation leaving the egg corresponding to action of a heart, theexistence of said cyclical variation indicating that the egg is viable.

In one aspect the invention is particularly suitable for use indetermining the viability of rare and exotic eggs (e.g. parrots) wherespeed of determination is less important than the accuracy of thedetermination.

The use of infra-red light is preferred for two reasons, (1) attenuationof infra-red light passing through eggs is much lower than with light atoptical wavelengths, and (2) infra-red light can impinge on the egg fora much longer period without heating the egg. The egg can be damaged byheat when candling with optical light if the egg is left in front of theoptical source for too long.

Although the applicant believes that the periodic attenuation of thereceived radiation will be superimposed on optical light, it is toodangerous to place the egg in front of an optical light source to enablethe apparatus of the invention to obtain the cyclical variation. This isbecause in order to penetrate and pass right through the egg,particularly in dark pigment eggs, light at optical wavelengths must beof such intensity that the egg is in danger of becoming overheated ifleft near the light source for any appreciable length of time (more than3 or 4 seconds).

One advantage of at least preferred arrangements is that a user canobtain a virtually instant indication of the viability of the egg i.e.whether it is alive or not. Furthermore, such arrangements mitigate thedangers to which the above mentioned methods have exposed eggs. Afurther advantage is that much “guesswork” is taken out of priorartificial incubation techniques since the apparatus enables an accurateheart rate of the animal inside the egg to be obtained which indicateswhether incubating conditions are optimised. A further advantage is thatsuch arrangements enable the viability of the egg to be determinedthroughout the incubation period to hatching of the young animal.“Background infra-red radiation” means radiation from unwanted sources,for example artificial lighting and daylight. The applicant has foundthat the presence of such radiation renders the apparatus difficult touse and inhibits detection of the varying intensity of the radiationthat has passed through the egg. The emitting means may emit infra-redat a single wavelength or over a band of wavelengths simultaneously.

Further feature of the apparatus are set out in claims 2 to 11 to whichattention is hereby directed.

Advantageously, the detecting means are shielded from detectingelectromagnetic radiation emitted directly from said emitting means.This helps to ensure that the output from the detecting means ismeaningful. Since some radiation is reflected off the shell of the egg,this shielding also inhibits radiation that has not passed through theegg from reaching the detecting means.

Preferably, the detecting means is positioned to inhibit detection ofelectromagnetic radiation emitted directly from said emitting means. Inone embodiment, the detecting means is shielded by positioning so that,in use, the egg lies between the emitting means and detecting means. Inanother embodiment, the detecting means is both positioned to inhibitdetection of electromagnetic radiation emitted directly from saidemitting means and provided with a physical shield.

Advantageously, said emitting means emit electromagnetic radiation overa limited angle. This helps to ensure that the detecting means onlydetects radiation that has passed through the egg.

Preferably, the limited angle is adjustable. By making the angleadjustable, and hence the amount of infra-red impinging on the egg, auser is able to adjust the apparatus to achieve an optimum output fromthe detecting means. In one embodiment the apparatus is provided with aplurality of emitting means that each have a different limited angle. Inuse, a user can switch between each emitting means to obtain the bestresults.

Advantageously, the emitting means emit electromagnetic radiation in thewavelength range 720 nm to 940 nm.

Preferably, the emitting means emit electromagnetic radiationpredominantly at a wavelength of 875 nm. The applicant has found thatthis produces the strongest outputs from the detecting means withchicken eggs.

Advantageously, the apparatus further comprises a support means forsupporting an egg in a position within the apparatus.

Preferably, the detecting means are located adjacent said support means.In one embodiment the detecting means are located within said supportmeans, the arrangement being such that, in use, electromagneticradiation can reach the detecting means only by passing through the egg.This is particularly advantageous because, in use, the egg and supportmeans enclose the detecting means so that only radiation that has passedthrough the egg can be detected.

Advantageously, the support means comprises a deformable material thatprovides a point of contact with an egg, the material deforming to partof the contours of the egg under the egg's weight. This provides a“seal” inhibiting penetration of unwanted infra-red radiation, thatmight be detected by the detecting means.

Preferably, the deformable material comprises latex. In one embodiment,the latex comprises a black dye. The applicant has found thisparticularly effective since the combination inhibits penetration ofunwanted infra-red radiation and at the same time provides a supportthat minimises potential for damage to the egg.

Advantageously, the support means are mounted on a base.

Preferably, the base comprises an elastic material, preferably foamrubber, to inhibit damage to an egg should it be dropped onto the base.

Advantageously, the support means comprises a suction cup.

Preferably, said shielding means comprises a housing having a firstmember and a second member moveable with respect to the first memberfrom a position in which an egg can be inserted into the apparatus to aposition in which the egg is shielded from background infra-redradiation. In one embodiment, the detecting means and emitting means aremounted on the first member.

Preferably, the apparatus further comprises a power source. Oneadvantage of this is that the apparatus may be hand-held which makes iteasy to use in the field.

According to another aspect of the present invention there is provided amethod for determining the viability of an egg, which method comprisesthe steps of:

-   -   (1) placing an egg in an environment that is shielded from        background infra-red radiation;    -   (2) emitting electromagnetic radiation at infra-red        wavelength(s) from emitting means toward the egg;    -   (3) detecting at least a part of said electromagnetic radiation        that has passed through the egg with detecting means and        generating an output signal therefrom; and    -   (4) processing said output signal to determine whether there is        a cyclical variation in the intensity of the infra-red radiation        leaving the egg corresponding to action of a heart, the        existence of said cyclical variation indicating that the egg is        viable.

Further steps of the method are set out in claims 31 to 49 to whichattention is hereby directed.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, reference will nowbe made by way of example to the accompanying drawings in which:

FIG. 1 is a schematic cross section through a seven-day old chickenembryo showing its embryonic membranes and embryonic blood vessels;

FIG. 2 is a schematic cross section through an egg containing the embryoof FIG. 1 shown at four points during its development;

FIG. 3 is a schematic perspective view of part of an apparatus inaccordance with the present invention, the lid being removed forclarity;

FIG. 4 is a schematic perspective view of a lid suitable for use withthe apparatus of FIG. 3;

FIG. 5 is a schematic view of the apparatus of FIG. 1 fitted with thelid of FIG. 4;

FIG. 6 is a schematic cross section through an apparatus in accordancewith the present invention, part of the apparatus omitted for clarity,in use determining the viability of an egg;

FIG. 7 is a flow diagram showing the steps of a method in accordancewith the present invention;

FIG. 8 is a circuit diagram of the amplification and filtering stages anapparatus in accordance with the present invention;

FIG. 9 is a block diagram of the algorithm used to manipulate theamplified output signal of the detector used in the apparatus of theinvention;

FIG. 10 is a schematic graph showing the method of detecting thecyclical variation in intensity of light received by the detector; and

FIGS. 11, 12 and 13 show various examples of traces of voltage (Y-axis)against time (X-axis) that can been seen on a screen of an apparatus inaccordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1 and 2, for an understanding of the background tothe present invention some details of a chicken embryo 1 developingwithin a shell 2 are shown. It is to be noted that the structure of thechicken egg is very similar to that of a wide variety of egg-layinganimals. The embryo 1 comprises a yolk sac 3 within which blood vessels5, known as the vitelline vessels, extract nutrients and convey them tothe embryo. Another structure 4 known as the allantois assists therespiratory cycle of the embryo. As the embryo 1 grows the allantois 4is pressed against the inner surface of the shell 2 where thecapillaries in the allantois can readily exchange carbon dioxide foroxygen that has passed through the pores of the shell. Under action ofthe animal's heart the blood vessels 6 in the allantois 4 swell andcontract in a cyclical fashion. Furthermore, as is apparent from FIG. 2,the allantois 4 grows as the embryo 1 develops so that it covers anincreasing surface area adjacent the inner side of the shell 2. Therespiratory function of the allantois 4 begins approximately at three tofour days from the beginning of the incubation period and ceases whenthe chick breaks out of the egg and breathes of its own accord. To thebest of the applicant's knowledge and belief no apparatus and method hasbeen proposed up to now that takes advantage of the cyclically variableblood flow through the vessels of the allantois and/or the vitellinevessels, caused by the animal's heart, to monitor the viability of thegrowing embryo within the egg.

Referring to FIGS. 3 to 6, an apparatus generally identified byreference numeral 10 comprises a housing 12 and a lid 14. As shown inFIG. 3, the lid 14 can be mounted on the housing 12 via inwardprojections 16 on the lid 14 that locate with recesses 18 on the housing12 and permit rotational movement of the lid 14 with respect to thehousing 12. The lid 14 is constructed from plastics material thatprevents the passage of infra-red radiation through its walls.

The housing 12 comprises two sections, a first section 20 and a secondsection 22. The first section 20 comprises a liquid crystal display 24,control buttons 26, a power source (not shown) and various electronicprocessing equipment (not shown) that will be described in greaterdetail below. The second section 22 comprises a box 28 open at its upperside and having five walls constructed from plastics material thatprevent passage of infra-red radiation. Thus, when the lid 14 is in aclosed position on the box 28 the volume that is enclosed is shieldedfrom background infra-red radiation. A source 30 is mounted on the box28 adjacent the second section 22 and is positioned so that it can emitelectromagnetic radiation into the box 28. The source 30 is an infra-red(IR) emitter manufactured and sold by Hewlett Packard (part numberHSDL-4230) that can emit IR over a wavelength range of 720-940 nm, withpeak intensity at approximately 875 nm. It has a power rating of 75mW/sr at 50 mA and a beam angle of 17°, the axis of the beam lying on aperpendicular to plane of the wall on which it is mounted. The applicanthas found that the power of infra-red from the source 30 does not appearto cause any damage to the egg under test. An infra-red detector 32 ismounted in the base of box 28 and is designed and positioned to detectIR that has been emitted by the source 30. The detector 32 ismanufactured by Texas Instruments as component TSL 250 and is availablefrom Pacer Components (Berkshire, England). It will be noted that theradiation emitted from the source 30 does not directly intersect withthe detector 32.

Mounted on the bottom of the box 28 and around the detector 32 is aholder 34 which comprises an inverted suction cup manufactured fromlatex so as to be deformable. The suction cup is different to knownsuction cups in that a black dye has been added during manufacture toinhibit passage of light at infra-red wavelengths. In use, an egg can beplaced on and supported by the holder 34 and the latex deforms to thecontours of that part of the egg with which it is in contact. The eggcan be supported in any orientation by the holder 34. No suction isapplied via the holder 34. The distance x as shown in FIG. 4 is 0.05 m,although this does not appear critical and the source 30 may abut an eggor be further away.

In use, the lid 14 of the apparatus 10 is opened and an egg 36 (see FIG.6) who's viability is to be determined is placed on the holder 34. Thelid 14 is closed, placing the egg 34 in darkness and shielding it fromIR. One of the buttons 26 on the housing 12 is pressed and, undercontrol of electronic circuitry (not shown) in the second section 22,source 30 is activated and emits IR radiation 38 toward the egg 34continuously until the apparatus is de-activated by the user. Uponreaching the egg 34 part of the radiation 38 is reflected off the shellof the egg 34 and part passes through the shell into the inside of theegg. It will be noted that the holder 34 inhibits radiation that hasbeen reflected from the outside of the egg from being detected by thedetector 32. As shown in FIG. 5 some of radiation 38 is repeatedlyreflected off the inner side of the shell, some passes straight throughand some is ultimately reflected through 90° i.e. in the direction ofdetector 32. Upon leaving the egg 34 it is likely that some radiation 38passes across the allantois (not shown in FIG. 6) inside the shell, andwhen in the early stages of incubation across the yolk sac containingthe vitelline vessels. As described above, the allantois is responsiblefor intake of oxygen and expulsion of CO₂ from the egg as part of therespiratory cycle of the developing animal. Blood vessels inside thismembrane continually swell and contract under the action of the animal'sheart. Accordingly, as IR radiation 38 passes across this structure,some has to pass through more blood (when the blood vessels are swollenor swelling) and some passes through less blood (when the blood vesselsare contracted or contracting). This results in a cyclical variation inthe intensity of the IR radiation leaving the egg 36 that is a directfunction of the animal's heart rate. The electrical output signal fromthe detector 32 also varies in the same way, the variation being of theorder of approximately 0.2 mV to 1 mV. It is believed that is it is theblood vessels in the allantois that are primarily responsible forcausing the cyclical variation in intensity of received infra-red.However, it might be possible that other structures are responsible forthe cyclical variation, particularly the vitelline vessels when the eggis in the early stages of incubation and the yolk sac is still large.

Referring to FIG. 7 the output signal from the detector 32 is processedby electronic processing equipment located in the first section 20 ofthe housing 12. The signal is first amplified and then filtered at stage40.

Stage 40 is shown in greater detail in FIG. 8. The output signal fromthe detector is of the order of approximately 200 mV upon which the timevarying voltage of the order of a few mV is superimposed as describedabove. It is this time varying signal that the circuitry is designed toextract and amplify. The output signal first passes through a capacitor48 to extract the time varying part of the signal. This time varyingsignal passes to a first gain stage 50 that applies a gain of 10 andalso filters the signal with the capacitor 52. The capacitor 52 acts asa low pass filter with a filter corner frequency of 15 Hz i.e. the 15 Hzcomponent of the input signal is reduced by 3 dB at this stage. 15 Hzcorresponds to a heart rate of approximately 900 beats per minute, overwhich it is unlikely any animal's heart will beat, but also well belowthe 50 Hz signal generated by mains electricity. The signal then passesto a second gain stage 54 that applies a gain of between 4.13 and 45.45,depending on the value of variable resistor 56 (variable between 0 and22 kΩ). The signal is also filtered at stage 54, the capacitor 55 beinga low pass filter with a filter corner frequency of 33 Hz i.e. the 33 Hzcomponent of the input signal is reduced by 3 dB at this stage. Becauseof electrical interference in the wires generated for example byinduction from mains power lines it is necessary to further filter thesignal; if the signal is not further filtered the time varying signalcorresponding to the variation in intensity of the received IR would betotally drowned out by interference and noise. Accordingly, the signalthen passes through a first filter stage 58 that applies a gain of1.068, onto a second filter stage 60 that applies a gain of 1.58 andonto a third filter stage 62 that applies a gain of 2.50. Each filterstage is a low pass filter having a filter corner frequency set at 16 Hzi.e. the 16 Hz component of the input signal is reduced by 3 dB at eachstage. Having been filtered, the signal passes through a final thirdgain stage 64 that applies a gain of 10 and a final low pass filteringof the signal with a corner frequency at 33 Hz. Accordingly the overallgain on the time varying signal is between 1742 and 19180 rememberingthat this is because of the variable resistor 56, and the signal hasbeen filtered at 24 dB per octave (mainly due to the effect of filteringat stages 50, 58, 60 and 62). In the actual apparatus made by theapplicant the variable resistor 56 can be adjusted at the point ofmanufacture and is set to give the maximum gain. However, it is notadjustable by the user. The signal then leaves this section of theapparatus and moves onto the analogue to digital converter.

Referring again to FIG. 7 at stage 42 the signal is converted fromanalogue to digital and processed by a microcontroller (not shown). Thesteps of the digital signal processing are shown in greater detail inFIG. 9. The microcontroller is programmed to set up a band stop filter84, that is it looks for that part of the signal having voltageamplitude greater than a preset voltage and that part of the signalhaving voltage amplitude lower than a preset voltage. The values of theband stop filter are between 2.0V and 2.9V. The time varying signal withwhich the apparatus is concerned is periodic by nature and when an eggis appropriately positioned the peaks 86, 88 of this signal will appearat either side of the band stop filter. Random error noise 90 will alsooccasionally appear at either side of the band stop filter; however, thealgorithms programmed into the microcontroller are designed to extractthe periodic signal and reject signals generated by random error noisethat may not be hidden by the band stop filter.

Referring to FIGS. 9 and 10 the first step 66 of the algorithm involvesmonitoring the band stop filter 84 and waiting for a signal to appear ateither side. This monitoring is continuous. Whilst the algorithm iswaiting for its first pair of signals 86, 88 the user sees a flat traceon the display and the numerical value of beats per minute displayed tothe user is zero. When a first signal 86 does appear, the algorithmmoves to step 68 in which it looks for a second signal 88; if it doesnot detect one it simply continues to wait whilst still monitoring. Ifthe algorithm does detect a second signal 88 it moves to step 70 inwhich the time interval in beats per minute (bpm) is calculated betweenthe detection of the first signal 86 and detection of the second signal88. In the same stage the algorithm checks whether the calculated timeinterval falls within the range 30 to 600 bpm; if it does not thesignals are rejected, whereas if it does the algorithm moves to step 72in which the time interval is stored in the microcontroller's memory. Atstep 74 the algorithm checks the number of intervals that are stored inmemory. If the number is less than four, it waits for further timeintervals to be received at step 76. If the number is equal to four thealgorithm calculates the average bpm from the four intervals at step 78.Using four intervals to calculate the average bpm is useful as thisreduces the chance of noise affecting the result. A further advantage isthat the average bpm will vary more gradually than a real time displayof the bpm that may fluctuate rapidly. Finally, the algorithm checksthat the calculated average bpm lies in the range 30 to 600 bpm at stage80 (an animal's heart rate is unlikely to go above 600 bpm; at present ahigh heart rate that the applicant has measured was 250 bpm in a chickenegg (bantam)). If it is not, the calculated average is discarded atstage 82. If it is in the range the numerical value of bpm is displayedto the user on display 24 at stage 44 (see FIG. 7) together with a traceof voltage versus time that represents the heart rate of the animal inthe egg. The trace is generated from the actual output signal, althoughit could be generated from the calculated average bpm. However, usingthe output signal enables the user to see if the apparatus has generateda spurious result, for example if there is a lot of repetitive noise inthe signal. It should be noted that the microcontroller only ever storesa maximum of four intervals. When a new interval is received the oldestinterval is removed to make room for the new interval. In this mannerthe information displayed to the user is always the latest andeffectively provides a real time display of the heart rate of theanimal.

If no cyclical variation is obtained from the detector the display 24indicates that the egg is not viable and the trace shows a flat lineindicating IR being received by the detector 32 at a constant rate (FIG.11). If the egg is viable a trace similar to that shown in FIG. 12 isseen.

The applicant has found that, even if the egg is viable, it is notalways possible to obtain a satisfactory output from the detector 32. Inparticular, this occurs if the animal moves inside the egg or if theinfra-red does not pass through a sufficiently big blood vessel as itexits the egg. If the animal is moving the trace on display 24 is rapid,erratic and the pulse is exaggerated. If the egg is in a bad position,the trace shows faint pulse line i.e. greatly reduced in magnitude (FIG.13), but not a flat line as with a non-viable egg. In this situation,the algorithms at stage 42 cause the display to show a signal to theuser either that animal is moving or that the egg is badly positionedwhich prompts the user to wait or re-position the egg. A user may needto re-position the egg between 1 and 3 times to be sure that an egg isnot viable, and preferably repeat the process at several intervals of 24hours in order to be completely sure that the egg is not viable.Although the apparatus indicates the viability almost immediately, theeggs of some species are too valuable to discard on the basis of onereading. The electronic processing equipment continually monitors thereceived signal and as soon as a viable signal is received the heartrate trace and beats per minute are displayed.

The applicant has also found that the best signal is obtained when theradiation impinges on an egg from its side i.e. substantiallyperpendicular to its longitudinal axis, and the detector 32 is locatedbelow the egg with its detection axis substantially perpendicular to theaxis of the source 30. However, in the early stages of development ofthe egg, the detector 30 and source 32 can be placed anywhere around theegg or the egg placed at any orientation within the apparatus 10 toobtain a signal. When the egg is more developed, the animal occupies somuch of the volume of the egg that only a narrow range of positionsobtains a satisfactory signal. One of these positions is shown in FIG. 4and is further advantageous because the egg can be readily supported inthis position. The applicant has also found that when nearly fullydeveloped, the best signals are obtained when the radiation impinges onthe rounded or “blunt” end of the egg and passes through the air sackinside, thus still passing through the structures mentioned above butnot being obstructed by the animal.

Important variations of the above embodiment are that the electronicprocessing equipment may be separate from the box in which the egg isplaced i.e. the first section 20 may be separate from the second section22. If no signal is obtained from the detecting means, the display 24may prompt the user to move the egg and/or re-activate the apparatus sothat the viability is determined over a number of interrogations, thusminimising the chances of error.

The apparatus may be incorporated into known incubators to provide an“all-in-one” arrangement for incubating eggs.

The apparatus described in the preferred embodiment is designed to behand-held and portable. However, this is not essential.

1. An apparatus for determining the viability of an egg, which apparatus comprises shielding means, emitting means and detecting means, the arrangement being such that, in use, the shielding means inhibits exposure of an egg to background infra-red radiation, said emitting means can emit electromagnetic radiation that impinge on the blunt end of the egg, and the detecting means are positioned to detect at least a part of said electromagnetic radiation that has passed through the egg, the apparatus further comprising means for processing an output signal of the detecting means to determine whether there is a cyclical variation in the intensity of the radiation leaving the egg corresponding to action of a heart, the existence of said cyclical variation indicating that the egg is viable, characterised in that said emitting means and said detecting means can emit and detect electromagnetic radiation at infra-red wavelength(s) respectively, whereby said cyclical variation may be detected up until the animal hatches from the egg.
 2. An apparatus as claimed in claim 1, further comprising means for providing a visual display trace on which any cyclical variation is apparent.
 3. An apparatus as claimed in claim 1, wherein said means for processing can determine a heart rate and said apparatus further comprises means for a displaying a numerical indication of the heart rate.
 4. An apparatus as claimed in claim 1 wherein the means for processing extracts only variation in the output signal.
 5. An apparatus as claimed claim 1 further comprising means for applying a gain to said output signal or cyclical variation.
 6. An apparatus as claimed in claim 5, wherein said gain is between approximately 1500 and
 20000. 7. An apparatus as claimed in claim 1, wherein said processing means can filter the output signal to remove at least some of the noise in the output signal.
 8. An apparatus as claimed in claim 1, wherein said processing means can extract the time interval between successive points in the cyclical variation in order to calculate a heart rate therefrom.
 9. An apparatus as claimed in claim 8, wherein said processing means can compare the calculated heart rate against a predetermined range to ensure that the calculated heart rate lies within the range to inhibit the effect of random noise.
 10. An apparatus as claimed in claim 8, wherein said processing means can extract a plurality of time intervals, and is able to calculate an average time interval and an average heart rate therefrom.
 11. An apparatus as claimed in claim 10, wherein said processing means can compare the calculated average heart rate against a predetermined range to ensure that the calculated average heart rate lies within the range to inhibit the effect of random noise.
 12. An apparatus as claimed in claim 1, wherein the detecting means are shielded from detecting electromagnetic radiation emitted directly from said emitting means.
 13. An apparatus as claimed in claim 1, wherein the detecting means are positioned to inhibit detection of electromagnetic radiation emitted directly from said emitting means.
 14. An apparatus as claimed in claim 1, wherein said emitting means emit electromagnetic radiation over a limited angle.
 15. An apparatus as claimed in claim 14, wherein said limited angle is adjustable.
 16. An apparatus as claimed in claim 1, wherein the emitting means emit electromagnetic radiation in the wavelength range 720 nm to 940 nm.
 17. An apparatus as claimed in claim 16 wherein the emitting means emit electromagnetic radiation predominantly at a wavelength of 875 nm.
 18. An apparatus as claimed in claim 1, further comprising a support means for supporting an egg in a position within the apparatus.
 19. An apparatus as claimed in claim 18, wherein said detecting means are located adjacent said support means.
 20. An apparatus as claimed in claim 19, wherein said detecting means are located within said support means, the arrangement being such that, in use, electromagnetic radiation can reach the detecting means only by passing through the egg.
 21. An apparatus as claimed in claim 18 wherein the support means comprises a deformable material that provides a point of contact with an egg, the material deforming to part of the contours of the egg under the egg's weight.
 22. An apparatus as claimed in claim 21, wherein the deformable material comprises latex.
 23. An apparatus as claimed in claim 22, wherein the latex comprises a black dye to inhibit the passage of infra-red radiation.
 24. An apparatus as claimed in claim 18, wherein the support means are mounted on a base.
 25. An apparatus as claimed in claim 24, wherein the base comprises an elastic material, preferably foam rubber, to inhibit damage to an egg should it be dropped onto the base.
 26. An apparatus as claimed in claim 18, wherein the support means comprises a suction cup.
 27. An apparatus as claimed in claim 1, wherein said shielding means comprises a housing having a first member and a second member moveable with respect to the first member from a position in which an egg can be inserted into the apparatus to a position in which the egg is shielded from background infra-red radiation.
 28. An apparatus as claimed in claim 27, wherein the detecting means and emitting means are mounted on the first member.
 29. An apparatus as claimed in claim 1, further comprising a power source.
 30. A method for determining the viability of an egg, which method comprises the steps of: (1) placing an egg in an environment that is shielded from background infra-red radiation; (2) emitting electromagnetic radiation from emitting means toward the blunt end of said egg; (3) detecting at least a part of said electromagnetic radiation that has passed through the egg with detecting means and generating an output signal therefrom; and (4) processing said output signal to determine whether there is a cyclical variation in the intensity of the radiation leaving the egg corresponding to action of a heart, the existence of said cyclical variation indicating that the egg is viable, characterised in that step (2) is performed by emitting electromagnetic radiation at infra-red wavelength(s) toward said egg and step (3) is performed by detecting electromagnetic radiation that has passed therethrough, whereby said cyclical variation may be detected up until the animal hatches from the egg.
 31. A method as claimed in claim 30, further comprising the step of providing a visual display trace on which any cyclical variation is apparent.
 32. A method as claimed in claim 30, further comprising the step of processing said output signal to determine a heart rate and displaying a numerical value of the heart rate to a user.
 33. A method as claimed in claim 30, further comprising the step of extracting only variation in the output signal.
 34. A method as claimed in claim 30, further comprising the step of applying a gain to said output signal or cyclical variation.
 35. A method as claimed in claim 34, wherein said gain is between approximately 1500 and
 20000. 36. A method as claimed in claim 30, further comprising the step of filtering the output signal to remove at least some of the noise in the output signal.
 37. A method as claimed in claim 30, further comprising the step of extracting the time interval between successive points in the cyclical variation in order to calculate a heart rate therefrom.
 38. A method as claimed in claim 37, farther comprising the step of comparing the calculated heart rate against a predetermined range to ensure that the calculated heart rate lies within the range to inhibit the effect of random noise.
 39. A method as claimed in claim 37, further comprising the step of extracting a plurality of time intervals, and calculating an average time interval and heart rate therefrom.
 40. A method as claimed in claim 39, further comprising the step of comparing the calculated average heart rate against a predetermined range to ensure that the calculated average heart rate lies within the range to inhibit the effect of random noise.
 41. A method as claimed in claim 30, further comprising the step of shielding the detecting means from radiation emitted directly from said emitting means.
 42. A method as claimed in claim 30, further comprising the step of positioning the detecting means to inhibit detection of radiation emitted directly by said emitting means.
 43. A method as claimed in claim 30, wherein step (2) is carried out by emitting infra-red over a limited angle.
 44. A method as claimed in claim 43, wherein the limited angle is adjustable.
 45. A method as claimed claim 30, wherein step (2) is carried out by emitting electromagnetic radiation in the wavelength range 720 nm to 940 nm.
 46. A method as claimed in claim 45, wherein the emitting means emit electromagnetic radiation predominantly at a wavelength of 875 nm.
 47. A method as claimed in claim 30, further comprising the step of supporting the egg on a support means.
 48. A method as claimed in claim 47, wherein step (3) is carried out by placing the detecting means adjacent the support means so that radiation can reach the detecting means only by passing through the egg.
 49. A method as claim in claim 31, wherein step (1) is carried out by placing the egg in a housing that can provide said shielding.
 50. An apparatus for determining the viability of an egg, which apparatus comprises emitting means and detecting means, the arrangement being such that, in use, said emitting means can emit electromagnetic radiation that impinges on the blunt end of the egg, and the detecting means are positioned to detect at least a part of said electromagnetic radiation that has passed through the egg, the apparatus further comprising means for processing an output signal of the detecting means to determine whether there is a cyclical variation in the intensity of the infra-red radiation leaving the egg corresponding to action of a heart, the existence of said cyclical variation indicating that the egg is viable, characterised in that said emitting means and said detecting means can emit and detect electromagnetic radiation at infra-red wavelength(s) respectively whereby said cyclical variation may be detected up until the animal hatches from the egg.
 51. A method for determining the viability of an egg, which method comprises the steps of: (1) emitting electromagnetic radiation from emitting means toward the blunt end of the egg; (2) detecting at least a part of said electromagnetic radiation that has passed through the egg with detecting means and generating an output signal therefrom; and (3) processing said output signal to determine whether there is a cyclical variation in the intensity of the infra-red radiation leaving the egg corresponding to action of a heart, the existence of said cyclical variation indicating that the egg is viable; characterised in that step (1) is performed by emitting electromagnetic radiation at infra-red wavelength(s) toward said egg and step (3) is performed by detecting electromagnetic radiation that has passed therethrough, whereby said cyclical variation may be detected up until the animal hatches from the egg. 